The most common and most likely answer to this crossword clue is the 9 letter word UNCHECKED
I've seen this crossword clue in The Daily Telegraph
U
N
C
H
E
C
K
E
D
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does UNCHECKED mean?
UNCHECKED adjective- Unrestrained, not held back.
- Not examined for accuracy, efficiency, etc.
- Of a check box: not checked (ticked or enabled).
- (crossword puzzles) Of a square: part of only one entry (that is, across or down, but not both).
- To remove a checkmark.
- (travel) To remove a previously checked-in passenger from the check-in system, allowing changes to the ticket.